The invention relates to machining processes and in particular to a machining process for gun tubes. Specifically, it relates to a device for machining a plurality of sectors, simultaneously, on gun tube screw threads.
Gun tube, thread sectoring, is a machining process where portions of the threaded portion are removed, by either a milling or slotting operation. A horizontal shaper may be used as a power source or by other means of pushing and returning the sectoring device.
In the present invention there are methods of holding a gun tube, rotating it into the part of the shaping tool, and a means of attaching a sectoring device to the power source; the invention, however, is primarily concerned with machining multi-thread sectors simultaneously.
The gun tube, screw thread, sectoring device is a multi-cutter shaping head. When attached to a suitable power source, equipped with a means to rotate the gun tube, this invention will cut a plurality of opposing sectors simultaneously.
It is to be noted that with modifications a plurality of non-opposing sectors may also be cut. It is also to be noted that the present invention may be arranged to cut various conditions of opposing sectors simultaneously, but for clarity and simplification the description of the present invention is presented for cutting four opposing sectors simultaneously.
Furthermore, it is also to be understood that the device of the present invention may be fabricated in a plurality of sizes to meet the parameters of size, shape, and dimensions of various different gun tubes. However, it is also to be understood that within certain parameters the gun tube, screw thread, sectoring device of this invention may be of universal configuration to handle and machine more than one size of gun tube.
In the prior art the sectoring of gun tube screw threads is performed by one of two methods. One method utilizes a form of milling cutter which removes the metal of one sector only. Thus, in a comparable job of four opposing sectors requires four set-ups; similarly, six opposing sectors requires six set-ups; in other words, in the prior art only one sector can be produced at a time in a horizontal milling machine.
The other method utilizes a hydraulic shaper, pushing a cutting tool through the length of the thread. After each pass, the tube must be indexed to bring more metal into the path that the cutting or shaping tool will follow. This method also produces only one sector for each machining set-up. The shaper cutting tool cannot be the full sector width, and this requires the indexing of the tube prior to the push stroke of the shaper. It is an the push stroke of the shaper that the cutting tool removes metal in front of the tool.
Thus, the big problem in the prior art is that only one sector is produced at each set up, so that a plurality of set-ups is required for any given gun tube screw thread sectoring operation. The present invention eliminates that problem.
The actuator of the present invention may be a hydraulic shaper or a similar facility to produce the necessary motion, such as a large hydraulic cylinder. For purposes of simplicity, any description of the present invention will refer to the use of a hydraulic shaper when necessary to relate to the power source.
The present invention relates only to the sectoring device; facilities used to actuate the device, hold or index the gun tube, or the use of an adapter to connect the sectoring device to the actuator may be referred to, but are not part of the sectoring device of this invention.
It is to be noted that the present invention may also be utilized to cut keyways or slots in comparable arrangement.
It is, therefore, an object of this invention to provide a device to produce gun tube screw thread sectors.
It is also an object of this invention to provide a device that will cut a plurality of gun tube screw thread sectors simultaneously.
It is another object of this invention to provide a device for producing gun tube screw thread sectors that can be activated by various means.
It is still another object of this invention to provide a device that will cut a plurality of gun tube screw thread opposing sectors simultaneously.
Further objects and advantages of the invention will become more apparent in light of the following description of the preferred embodiments.